Effects of alternative disinfection methods on the characteristics of effluent organic matter and the formation of disinfection byproducts.

The characteristics of effluent organic matter (EfOM) and the type of disinfection methods are closely related to the formation of disinfection byproducts (DBPs) in reclaimed water. In this study, five disinfection methods, i.e., chlorination, ultraviolet (UV) followed by chlorination (UV + Cl), UV/chlorine (UV/Cl), chloramination, and chlorine dioxide (ClO2), were applied to investigate the changes in the properties of EfOM, the formation of DBPs, and the relationship between EfOM properties and DBP formation during the disinfection of four secondary biological effluents. The results showed that EfOM with medium molecular weight (MW) (0.5-6 kDa) was the dominant fraction for all WWTPs. From a fluorescence perspective, the EfOM of the AAO process was rich in humic matter, while the EfOM of the oxidation ditch (OD) process was rich in protein matter. Disinfectants tended to transfer EfOM with high molecular weight (MW) (>6 kDa) to those with low MW (<0.5 kDa). Chlorination, UV + Cl and UV/Cl were more reactive to humic matter, while chloramination and chlorine dioxide were more reactive to protein matter. The formation of known DBPs was mainly dependent on humic matter, while protein matter was more likely to generate unknown DBPs. N-DBPs only accounted for 5.7%-17.7% of the total DBPs, but contributed more than 70% of the calculated toxicity, among which bromochloroacetonitrile (BCAN), dichloroacetonitrile (DCAN), and monobromoacetamide (MBAcAm) were the most important contributors to the calculated cytotoxicity. Monobromoacetic acid (MBAA) and MBAcAm were the primary drivers of the calculated genotoxicity. Overall, UV + Cl was the suggested optimal disinfection method for WWTPs.

Plasma-assisted assembly of Co3O4/TiO2-NRs for photoelectrocatalytic degradation of bisphenol A in solution and muddy systems.

Herein, Co3O4/TiO2-NRs electrodes with excellent photoresponse have been prepared via the plasma-assisted modification of Co3O4 on TiO2. With the combination of Co3O4 and TiO2, the composite electrode exhibited a red-shift phenomenon and the absorption of UV and visible light were enhanced to improve the light utilization efficiency. The Mott-Schottky diagram showed that a P-N heterojunction was successfully formed between Co3O4 and TiO2 on the electrode, which inhibited the recombination of electrons and holes, and had a high photocurrent density. In our photoelectrocatalysis (PEC) degradation experiments, the degradation rates of bisphenol A (BPA) by Co3O4/TiO2-NRs electrode in Na2SO4 and simulated seawater system reached 69.44 and 100%, respectively. The important role of ·O2-, ·OH, h+, and active chlorine (Cl·, HClO/ClO-, and Cl2) on the Co3O4/TiO2-NRs electrode during the degradation of BPA in simulated seawater was revealed. In addition, PEC combined with electrokinetic (EK) studies with the Co3O4/TiO2-NRs electrode were used for the degradation of BPA in muddy water, initially expanding the application scope of the PEC performance of the Co3O4/TiO2-NRs electrode for pollutants degradation, and had great potential for the subsequent treatment of muddy water pollutants.

Impact of boiling on chemical and physical processes for reduction of halomethanes, haloacetonitriles, and haloacetic acids in drinking water.

Tap water is boiled by families across the globe in their daily life for cooking food and beverages, as well as for controlling some chlorine-resistant organisms to improve the water quality. However, the effects of boiling methods (heating temperature, heating modes, open or closed containers) on water quality, in particular the reduction of disinfection byproducts (DBPs), are unclear. This comprehensive research demonstrates that during the heating process, trihalomethanes (THMs) were markedly decreased, haloacetonitriles (HANs) were drastically reduced and sometimes completely removed, while haloacetic acids (HAAs) were reduced the least. Heating to boiling in open containers reduced DBPs concentrations more than heating in the closed containers. Residual chlorine from 0.1 to 5.0 mg/L did not affect the removal of HANs, but could increase concentrations of HAAs likely due to reaction of organic matter with chlorine at elevated temperatures. THMs demonstrated good removal at 0.1-1 mg/L residual chlorine, but less removal at 5 mg/L residual chlorine. Sodium chloride (salt), often added as seasoning agent in the process of family cooking, was found to have little effect on the removal of DBPs during cooking and boiling. Compared with the toxicity of DBPs in tap water, boiling could greatly reduce both the cytotoxicity and carcinogenicity through removal of DBPs. Consequently, boiling of tap water had a significant effect on reducing human exposure to DBPs and their associated toxicities.

Enhanced chlorination of diclofenac using ABTS as electron shuttle: Performance, mechanism and applicability.

Chlorination, one of the most common oxidation strategies, performed limited degradation capacity towards many emerging organic contaminants under neutral pH conditions. In this study, 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonate (ABTS) was discovered to possess an outstanding activation property towards free available chlorine (FAC) during the chlorination of diclofenac (DCF) among pH 6.0-9.5. ABTS radical (ABTS•+) primarily accounted for the elimination of DCF in the ABTS/FAC system, although hydroxyl radicals, reactive chlorine species, and singlet oxygen were also generated via the self-decomposition of FAC. ABTS acted as the electron shuttle to degrade DCF in the ABTS/FAC system, where ABTS was firstly oxidized by FAC to ABTS•+ via single electron transfer, and followed by the elimination of DCF with the generated ABTS•+. Eight DCF degradation intermediates were identified by LC/Q-TOF/MS, and four DCF degradation pathways were proposed. Real water bodies, humic acid, and the coexistent anions of Cl-, HCO3-, NO3-, and SO42- performed negligible influence on DCF removal in ABTS/FAC system. ABTS/FAC system was much superior to sole chlorination in terms of toxicity reduction and anti-interference capacity. Overall, this study innovatively introduced ABTS as the electron shuttle to enhance the oxidative capacity of FAC under neutral pH conditions and provided a new insight that the ABTS-like organic/synthetic components might play an important role in degrading emerging organic contaminants by chlorination in water treatment.

Process optimization and mechanism for removal of high-concentration chlorine from municipal solid waste incineration fly ash washing wastewater by Friedel's salt.

Waterwashing is an important pretreatment method for the reuse of municipal solid waste incineration (MSWI) fly ash. However, the presence of high levels of chlorides and small amounts of sulfides in the waterwashing solution makes it difficult to treat and reuse. Therefore, in this study, a calcium sulfate- Friedel's salt precipitation method was used to dechlorinate and desulfurize in the MSWI fly ash washing solution. This paper mainly focused on the chloride removal, and the effects of factors such as reagent ratios, temperature, and reaction time on chloride removal rate and the two-stage dechlorination and desulfurization process were optimized. The experimental results indicated that when the ratio in the first stage was n(Ca):n(Al):n(Cl) = 3:1.5:1, and in the second stage, n(Ca):n(Al):n(Cl) = 8:4:1, a chloride removal rate of up to 90.5% and a sulfide removal rate of over 99.88% could be obtained. The deposited particles were analyzed by using FE-SEM, XRD, and FTIR to investigate their size, morphology, phase composition, and functional groups. The study revealed that excessively high or low reagent ratios could reduce the interlayer spacing of Friedel's salt. Additionally, high temperatures led to the decomposition of Friedel's salt, and the dechlorination efficiency was affected.

Accelerated removal of naproxen in the iron-based peracetic acid activation system by chloride ions: Enhancement of reactive oxidative species via the formation of iron-chloride complexes.

Iron-based PAA activation process is a promising advanced oxidation process for water decontamination which depends on Fe(II) as the main reactive site for PAA activation, resulting in various reactive oxidative species (ROSs) generation. For practical application, the impact of water matrix chloride ion (Cl-) on ROSs production and contaminants removal should be carefully considered. In this study, it's found that the introduction of Cl- (0.1-10 mM) could significantly enhance the reaction rate of the rapid stage (kobs1) up to 2.15 times at the initial pH of 4.25 in the Fe(II)/PAA system. Further studies demonstrated that the improved removal capacity of NAP resulted from Cl- induced R-O• generation as indicated by the exposure dose of R-O• increasing from 7.74 × 10-11 M•s to 1.44 × 10-10 M•s, rather than chlorine-containing radicals' generation. DFT calculation results suggested that the formed Fe(II)-Cl- complexes could easily activate PAA to generate more ROSs for NAP removal. Moreover, Fe(II)/PAA treatment can alleviate the biological toxicity of pollutants via both the Escherichia coli test and toxicity assessment. The obtained new knowledge manifested that Cl- can boost ROSs generation and conversion in iron-based PAA systems, providing guidance for the efficient decontamination of chlorine-containing sewage with PAA-based AOPs.

Simultaneous realization of heavy metal Cd solidification and chloride separation in municipal solid waste incineration fly ash: Mechanism and DFT analysis.

The solidification of heavy metals and the separation-recycling of chloride salts are effective approaches for the safe disposal of municipal solid waste incineration (MSWI) fly ash. This study achieved the solidification of the excessive heavy metal Cd by transforming MSWI fly ash into a solidified body mainly composed of ettringite, while also purifying the calcium and sulfate ions in the chloride solution. The research results demonstrate that the introduction of aluminum ions rapidly decreases the pH value of the MSWI fly ash reaction system. By adjusting the reaction system to a pH value of 11.50, the conversion rate of calcium ions reaches 99.68%, the separation rate of chloride reaches 95.99%, and the solidification rate of heavy metal Cd reaches 98.92%. Density functional theory (DFT) calculations indicate that the vacancy formation at the Ca-2 position of ettringite and Cd entering the vacancy has a higher probability. The combination of DFT calculations and experiments validates that heavy metal Cd leads to charge redistribution, increased interplanar spacing, and decreased thermal stability of ettringite. The concentration of calcium ions in the solution decreases to 22.64 mg/L, achieving efficient recovery of sodium chloride and potassium chloride in a shorter process. The ettringite-based solidified body contains 0.87% chloride ions, showing potential for resource utilization in cement-based materials.

Efficacy and safety of isotonic versus hypotonic intravenous maintenance fluids in hospitalized children: an updated systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Iatrogenic hyponatremia is a common complication following intravenous maintenance fluid therapy (IV-MFT) in hospitalized children. Despite the American Academy of Pediatrics' 2018 recommendations, IV-MFT prescribing practices still vary considerably. OBJECTIVES: This meta-analysis aimed to compare the safety and efficacy of isotonic versus hypotonic IV-MFT in hospitalized children. DATA SOURCES: We searched PubMed, Scopus, Web of Science, and Cochrane Central from inception to October 1, 2022. STUDY ELIGIBILITY CRITERIA: We included randomized controlled trials (RCTs) comparing isotonic versus hypotonic IV-MFT in hospitalized children, either with medical or surgical conditions. Our primary outcome was hyponatremia following IV-MFT. Secondary outcomes included hypernatremia, serum sodium, serum potassium, serum osmolarity, blood pH, blood sugar, serum creatinine, serum chloride, urinary sodium, length of hospital stay, and adverse outcomes. STUDY APPRAISAL AND SYNTHESIS METHODS: Random-effects models were used to pool the extracted data. We performed our analysis based on the duration of fluid administration (i.e., ≤ 24 and > 24 h). The Grades of Recommendations Assessment Development and Evaluation (GRADE) scale was used to evaluate the strength and level of evidence for recommendations. RESULTS: A total of 33 RCTs, comprising 5049 patients were included. Isotonic IV-MFT significantly reduced the risk of mild hyponatremia at both ≤ 24 h (RR = 0.38, 95% CI [0.30, 0.48], P < 0.00001; high quality of evidence) and > 24 h (RR = 0.47, 95% CI [0.37, 0.62], P < 0.00001; high quality of evidence). This protective effect of isotonic fluid was maintained in most examined subgroups. Isotonic IV-MFT significantly increased the risk of hypernatremia in neonates (RR = 3.74, 95% CI [1.42, 9.85], P = 0.008). In addition, it significantly increased serum creatinine at ≤ 24 h (MD = 0.89, 95% CI [0.84, 0.94], P < 0.00001) and decreased blood pH (MD = -0.05, 95% CI [-0.08 to -0.02], P = 0.0006). Mean serum sodium, serum osmolarity, and serum chloride were lower in the hypotonic group at ≤ 24 h. The two fluids were comparable in terms of serum potassium, length of hospital stay, blood sugar, and the risk of adverse outcomes. LIMITATIONS: The main limitation of our study was the heterogeneity of the included studies. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Isotonic IV-MFT was superior to the hypotonic one in reducing the risk of iatrogenic hyponatremia in hospitalized children. However, it increases the risk of hypernatremia in neonates and may lead to renal dysfunction. Given that the risk of hypernatremia is not important even in the neonates, we propose to use balanced isotonic IV-MFT in hospitalized children as it is better tolerated by the kidneys than 0.9% saline. SYSTEMATIC REVIEW REGISTRATION NUMBER: CRD42022372359. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Ecotoxicity and rapid degradation of quaternary ammonium compounds (QACs) subjected to combined vacuum UV and UV-C treatment.

Quaternary ammonium compounds (QACs) are active ingredients in a palette of commercially available disinfectants, sanitizers, and biocides. QACs are widely used because of their broad-spectrum antimicrobial properties but the ubiquitous uses have resulted in frequent detection in aquatic and terrestrial matrices including domestic wastewater, surface waters, urban soils and sediments. An increased domestic QACs consumption has increased the environmental occurrence, and investigation of mitigation methods and effects on non-target organisms are in demand. In this study, we examined the potential ecotoxicity of six QACs and investigated the effect of combined vacuum UV (185 nm) and UV-C (254 nm) irradiation (VUV/UVC) on degradation and mitigation of ecotoxicity of QACs. The study showed that combined VUV/UVC irradiation facilitated rapid degradation of benzalkonium chloride, benzethonium chloride, didecyldimethylammonium chloride, dodecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride. The estimated half-lives varied between 2 and 7 min, and degradation was affected by the initial QAC concentrations, the UV fluence, and the water matrix. The potential ecotoxicity of QACs and VUV/UVC treated QACs was examined using a battery of test organisms that included the luminescent bacterium Aliivibrio fischeri, the gram-negative and gram-positive bacteria Escherichiacoli and Enterococcus faecalis, the freshwater microalga Raphidocelis subcapitata, and the crustacean Daphia magna. The potential for trophic transfer of QACs was investigated in a simplified aquatic food web. Test organisms from different trophic levels were included to assess adverse effects of bioactive compounds in VUV/UVC treated samples including transformation products. The study showed that several QACs were highly toxic to aquatic test organisms with EC50 and/or EC20 values < 1 µM. VUV/UVC treatment of QACs resulted in substantial photolysis of the parent compounds and comprehensive mitigation of the ecotoxicity potential. VUV/UVC represent an attractive oxidation technology for abatement QACs in contaminated water because the process does not require addition of catalysts or precursors.

The role of reactive chlorine and nitrogen species in micropollutant degradation in UV/monochloramine.

Monochloramine (NH2Cl) is applied upstream of reverse osmosis (RO) membranes for biofouling control. Residual NH2Cl can undergo UV photolysis downstream, generating reactive species for an AOP to occur. At the bench-scale, NH2Cl is typically generated from combining sodium hypochlorite and ammonium chloride or sulfate. This study investigated the degradation of four compounds of interest - acetaminophen, caffeine, sucralose and 1,4-dioxane - in UV/NH2Cl at the bench scale to study their reactivity with reactive chlorine species (RCS) and reactive nitrogen species (RNS). With methanol acting as a scavenger of •OH radicals, the performance of UV/NH2Cl was compared to UV/H2O2 and UV/HOCl. In UV/H2O2, dioxane was severely inhibited at 1-2 mg/L H2O2 and comparable at 5 mg/L to UV/NH2Cl. When ammonium sulfate ((NH4)2SO4) was used as the ammonia source over ammonium chloride (NH4Cl), the overall degradation of micropollutants was higher and caffeine was exclusively degraded. At 1-2 mg/L NH2Cl, dioxane degraded by 16.2-17.8% and 2.92-5.29% from (NH4)2SO4 and NH4Cl respectively while caffeine degraded by 7.45-9.61% with NH2Cl ((NH4)2SO4), but not degrade with NH2Cl (NH4Cl). The higher concentration of chloride ions from NH4Cl significantly influenced the speciation of generated radicals and impacted micropollutant degradation. This suggests that the reactivity of more selective RCS (Cl2•-, •ClO, ClOH•-) and RNS (•NH2, •NO, •NO2, etc.) varies with micropollutants of interest. The presence of higher chloride concentration from the ammonia source inhibited the generation of •OH radicals with •OH consumed by RNS to form NO3- (µg/L levels), showing the impact of the choice of ammonia source and the water matrix on UV/NH2Cl performance.

Direct generation of DBPs from city dust during chlorine-based disinfection.

Chlorine-based disinfectants, such as sodium hypochlorite, are extensively used in our daily lives. In particular, during the recent Covid-19 pandemic and post-pandemic period, excessive amounts of chlorine-based disinfectants were used both indoors and outdoors to interrupt virus transmission. However, the interaction between disinfectants and city dust during the disinfection process has not been sufficiently evaluated. In this study, we conducted a comprehensive investigation into the intrinsic characteristics (e.g. morphology, size, elemental composition, and organic content, etc.) of dust collected from various indoor and outdoor areas. The results showed that the organic carbon content of indoor dust reached 6.14 %, with a corresponding measured dissolved organic carbon value of 4.17 ± 0.23 mg/g (normalized to the dust weight). Concentrations of regulated DBPs, resulting from the interaction between dust and NaClO, ranged from 57.78 ± 2.72 to 102.80 ± 22.63 µg/g for THMs and from 119.18 ± 6.50 to 285.14 ± 36.95 µg/g for HAAs (normalized to the dust weight). More significantly, using non-target analysis through gas chromatography quadrupole time-of-flight mass spectrometry (GC-qTOF-MS), we identified a total of 68, 89, and 87 types of halogenated DBPs from three typical indoor and outdoor sites (R-QH, C-JS, and W-BR, respectively). These unknown DBPs included compounds with higher toxicity compared to regulated DBPs. These findings highlight that city dust is a significant source of DBP generation during chlorine-based disinfection, posing potential harm to both the ecological environment and human health.

Singlet oxygen-mediated fluconazole degradation during the activation of chlorine dioxide with sulfite.

Singlet oxygen (1O2)-mediated advanced oxidations have received considerable attention due to their strong capacity to resist the water matrix and high selectivity for organic pollutants. In this study, the activation of chlorine dioxide with sulfite (sulfite/ClO2 process) to effectively produce 1O2 was proposed to degrade fluconazole (FLC) and simultaneously control the formation of disinfection byproducts (DBPs). The results revealed that FLC could be rapidly degraded by 78.6 % within 10 s by the sulfite/ClO2 process. Radical quenching tests and electron paramagnetic resonance (EPR) measurements confirm that 1O2 produced by the cleavage of epoxides formed by the combination of triazole electron-rich groups in FLC with peroxymonosulfate (PMS) was the main active species in the sulfite/ClO2 process. The degradation of FLC was favored under alkaline conditions because of the fast electron transfer rate at higher pH values. The presence of chloride (Cl-), bicarbonate (HCO3-), and humic acid (HA) hindered the degradation of FLC mainly because they compete with PMS for the electron-rich groups produced by the reaction. The degradation intermediates of FLC were identified by UPLC‒MS/MS, and their transformation pathways were deduced by the condensed Fukui function (CFF) theory. Using sulfite/ClO2 as a pretreatment process to treat real potable water, aldehydes, ketones, carboxylic acids and other intermediates may be produced via the carboxylation and carbonylation reactions mediated by 1O2, therefore promoting the formation of DBPs during the following chlorination. This study provided a new perspective that while 1O2 is effectively produced in the sulfite/ClO2 process for contaminant degradation, the formation of DBPs during subsequent chlorination should be cautioned.

Etlingera hemisphaerica Alters One-Dimensional Profile of Serum Proteins Due to Mercury Chloride in Rats (Rattus norvegicus).

<b>Background and Objective:</b> Several previous studies have shown that leaf ethanolic extract of <i>Etlingera hemisphaerica</i> (LE3H) has the potential to reduce the toxicity and teratogenicity effects of mercury. This study aimed to describe the effects of LE3H on the protein profile of <i>Rattus norvegicus</i> serum due to treatment with HgCl₂. <b>Materials and Methods:</b> Four groups of male rats, K1 was injected intraperitoneally (IP) HgCl₂ (5 mg kg¹ b.wt.), K2 was injected IP HgCl₂ (5 mg kg¹ b.wt.) and after 24 hrs it was gavage LE3H (0.27 mg g¹ b.wt.) every day for seven days, K3 was injected IP HgCl₂ (5 mg kg¹ b.wt.), after 24 hrs was gavage LE3H (0.55 mg g¹ b.wt.) every day for seven days. The K0 as control, received double-distilled water. On the ninth day, the experimental animals were killed via CD and blood was drawn from the heart to obtain serum. Serum samples were measured for protein content using the Lowry and serum was separated using the One-Dimensional Sodium dodecyl Sulfate-Polyacrylamide gel Electrophoresis (1D SDS-PAGE) technique. <b>Results:</b> The electropherograms showed four bands, 264.77, 219.53, 98.57 and 37.29 kDa, whose intensity significantly increased due to HgCl₂ treatment and then decreased to close to the control condition with LE3H administration. The results also revealed four bands, 31.95, 28, 06, 26, 29 and 15.09 kDa, whose intensity decreased significantly due to HgCl₂ treatment and then increased to close to the control condition by LE3H administration. <b>Conclusion:</b> The LE3H change profile of the eight blood serum protein bands due to HgCl₂ approximates the control condition in <i>R. norvegicus</i>.

Assessing seasonal fluctuations in leachate chemical properties and leachate pollution index as contamination indicators.

Municipal solid waste (MSW) management practices that lack scientific rigor and use impromptu methods have produced massive leachate in urban complexes. Nowadays, the management of leachate has become an utmost concern worldwide. The MSW landfill site was a low-lying, open dump that operated in a non-engineered way. In this context, the physicochemical characterization of leachate has been carried out. Leachate sampling was done at the Bhandewadi dumpsite, Nagpur, for three seasons (summer, rainy, and winter). During analysis, parameters such as COD, BOD5, pH, TKN, TSS, sulfates, and chlorides were analyzed, and the obtained data was compared with the standard EPA 2003 and CPHEEO 2016 methods. Values of COD, BOD5, TKN, sulfates, and chlorides were in the range of 2500-16,000 mg/L, 495-2500 mg/L, 167-1900 mg/L, 240-900 mg/L, and 1400-5900 mg/L with respect to all three seasons, respectively. In conjunction with physicochemical analysis, the landfill leachate's leachate pollutant index (LPI) was assessed. The highest LPI values were observed for summer (14.323) as compared to rainy (12.301) and winter (11.348) data. This index reflects the hazardous character of MSW leachate and the total potential for leachate contamination. The results of this study showed seasonal variations in the observed data. Age and seasonal fluctuations therefore substantially influence the composition of the leachate.

Daily rhythm in cortical chloride homeostasis underpins functional changes in visual cortex excitability.

Cortical activity patterns are strongly modulated by fast synaptic inhibition mediated through ionotropic, chloride-conducting receptors. Consequently, chloride homeostasis is ideally placed to regulate activity. We therefore investigated the stability of baseline [Cl-]i in adult mouse neocortex, using in vivo two-photon imaging. We found a two-fold increase in baseline [Cl-]i in layer 2/3 pyramidal neurons, from day to night, with marked effects upon both physiological cortical processing and seizure susceptibility. Importantly, the night-time activity can be converted to the day-time pattern by local inhibition of NKCC1, while inhibition of KCC2 converts day-time [Cl-]i towards night-time levels. Changes in the surface expression and phosphorylation of the cation-chloride cotransporters, NKCC1 and KCC2, matched these pharmacological effects. When we extended the dark period by 4 h, mice remained active, but [Cl-]i was modulated as for animals in normal light cycles. Our data thus demonstrate a daily [Cl-]i modulation with complex effects on cortical excitability.

Impact of clonal lineages on susceptibility of Staphylococcus lugdunensis to chlorhexidine digluconate and chloride benzalkonium.

BACKGROUND: Little is known about susceptibility of Staphylococcus lugdunensis to antiseptics. The objective of this study was to evaluate, at the molecular and phenotypic level, the susceptibility of 49 clinical S. lugdunensis strains (belonging to the seven clonal complexes [CCs] defined by multilocus sequence typing) to two antiseptics frequently used in healthcare settings (chlorhexidine digluconate [CHX] and chloride benzalkonium [BAC]). RESULTS: The minimum inhibitory concentrations (MICs), by broth microdilution method, varied for BAC from 0.25 mg/L to 8 mg/L (MIC50 = 1 mg/L, MIC90 = 2 mg/L) and for CHX from 0.5 mg/L to 2 mg/L (MIC50 = 1 mg/L, MIC90 = 2 mg/L). The BAC and CHX minimum bactericidal concentrations (MBCs) varied from 2 mg/L to 8 mg/L (MBC50 = 4 mg/L, MBC90 = 8 mg/L) and from 2 mg/L to 4 mg/L (MBC50 and MBC90 = 4 mg/L), respectively. A reduced susceptibility to CHX (MIC = 2 mg/L) was observed for 12.2% of the strains and that to BAC (MIC ≥ 4 mg/L) for 4.1%. The norA resistance gene was detected in all the 49 isolates, whereas the qacA gene was rarely encountered (two strains; 4.1%). The qacC, qacG, qacH, and qacJ genes were not detected. The two strains harboring the qacA gene had reduced susceptibility to both antiseptics and belonged to CC3. CONCLUSION: The norA gene was detected in all the strains, suggesting that it could belong to the core genome of S. lugdunensis. S. lugdunensis is highly susceptible to both antiseptics tested. Reduced susceptibility to BAC and CHX was a rare phenomenon. Of note, a tendency to higher MICs of BAC was detected for CC3 isolates. These results should be confirmed on a larger collection of strains.

Decreased intracellular chloride enhances cell migration and invasion via activation of the ERK1/2 signaling pathway in DU145 human prostate carcinoma cells.

Our previous study revealed that changes of the intracellular Cl- concentration ([Cl-]i) affected cell proliferation in cancer cells. However, the role of Cl- on cell migration and invasion in cancer cells remains unanalyzed. Therefore, the aim of the present study is to investigate whether changes of [Cl-]i affects cell migration and invasion of cancer cells. In human prostate cancer DU145 cells, cell migration and invasion were enhanced by culturing in the low Cl- medium (replacement of Cl- by NO3-). We also found that DU145 cells in the low Cl- condition caused significant transient ERK1/2 activation followed by an increase of MMP-1 mRNA levels. Inhibition of ERK1/2 activation in the low Cl- condition reduced enhancement of MMP-1 mRNA levels and decreased cell migration and invasion. These observations indicate that [Cl-]i plays important roles in metastatic function by regulating the ERK1/2 signaling pathway in human prostate cancer cells, and intracellular Cl- would be one of the key targets for anti-cancer therapy.

L-Shaped Association of Serum Chloride Level With All-Cause and Cause-Specific Mortality in American Adults: Population-Based Prospective Cohort Study.

BACKGROUND: Chloride is the most abundant anion in the human extracellular fluid and plays a crucial role in maintaining homeostasis. Previous studies have demonstrated that hypochloremia can act as an independent risk factor for adverse outcomes in various clinical settings. However, the association of variances of serum chloride with long-term mortality risk in general populations has been rarely investigated. OBJECTIVE: This study aims to assess the association of serum chloride with all-cause and cause-specific mortality in the general American adult population. METHODS: Data were collected from 10 survey cycles (1999-2018) of the National Health and Nutrition Examination Survey. All-cause mortality, cardiovascular disease (CVD) mortality, cancer mortality, and respiratory disease mortality data were obtained by linkage to the National Death Index through December 31, 2019. After adjusting for demographic factors and relevant lifestyle, laboratory items, and comorbid factors, weighted Cox proportional risk models were constructed to estimate hazard ratios and 95% CIs for all-cause and cause-specific mortality. RESULTS: A total of 51,060 adult participants were included, and during a median follow-up of 111 months, 7582 deaths were documented, 2388 of CVD, 1639 of cancer, and 567 of respiratory disease. The weighted Kaplan-Meier survival analyses showed consistent highest mortality risk in individuals with the lowest quartiles of serum chloride. The multivariate-adjusted hazard ratios from lowest to highest quartiles of serum chloride (≤101.2, 101.3-103.2, 103.2-105.0, and ≥105.1 mmol/L) were 1.00 (95% CI reference), 0.77 (95% CI 0.67-0.89), 0.72 (95% CI 0.63-0.82), and 0.77 (95% CI 0.65-0.90), respectively, for all-cause mortality (P for linear trend<.001); 1.00 (95% CI reference), 0.63 (95% CI 0.51-0.79), 0.56 (95% CI 0.43-0.73), and 0.67 (95% CI 0.50-0.89) for CVD mortality (P for linear trend=.004); 1.00 (95% CI reference), 0.67 (95% CI 0.54-0.84), 0.65 (95% CI 0.50-0.85), and 0.65 (95% CI 0.48-0.87) for cancer mortality (P for linear trend=.004); and 1.00 (95% CI reference), 0.68 (95% CI 0.41-1.13), 0.59 (95% CI 0.40-0.88), and 0.51 (95% CI 0.31-0.84) for respiratory disease mortality (P for linear trend=.004). The restricted cubic spline analyses revealed the nonlinear and L-shaped associations of serum chloride with all-cause and cause-specific mortality (all P for nonlinearity<.05), in which lower serum chloride was prominently associated with higher mortality risk. The associations of serum chloride with mortality risk were robust, and no significant additional interaction effect was detected for all-cause mortality and CVD mortality (P for interaction>.05). CONCLUSIONS: In American adults, decreased serum chloride concentrations were independently associated with increased all-cause mortality, CVD mortality, cancer mortality, and respiratory disease mortality. Our findings suggested that serum chloride may serve as a promising cost-effective health indicator in the general adult population. Further studies are warranted to explore the potential pathophysiological mechanisms underlying the association between serum chloride and mortality.

Biocidal and synergistic effect of three types of biologically synthesised silver/silver chloride nanoparticles.

Three types of silver/silver chloride nanoparticles were obtained by green synthesis from three types of microbial biomass. Their biocidal capacity was tested against six microorganisms. Two filamentous fungi were used that had previously demonstrated the ability to synthesise nanoparticles, Penicillium sp. 8L2 and Botryosphaeria rhodina MAMB-05. Also, the synthesis capacity of a yeast, Rhodotorula mucilaginosa 1S1, was evaluated. The original protocols underwent slight modifications. At the same time, the fractional inhibitory concentration was obtained. The interaction between specific antibiotics and the nanoparticles that showed the greatest biocidal capacity came from Penicillium sp.8L2, and it was studied further. All nanoparticles were characterised by UV-vis spectrophotometry and transmission electron microscopy (TEM). Also, their size distribution was analysed, which was in the range of 4 to 34 nm. The biocidal capacity of the nanoparticles for a group of bacteria and fungi was studied, presenting very low values in the range of 2.5-10 µg/mL for bacteria and 4-256 µg/mL for fungi. The interactions between the nanoparticles synthesised by Penicillium sp. 8L2 and a group of specific antibiotics for the tested microorganisms were also studied, proving that there was a synergistic interaction with vancomycin and ciprofloxacin and Staphylococcus epidermidis CECT 4183 and Escherichia coli CECT 101 bacteria, respectively.

Analytical Methods Based on the Mass Balance Approach for Purity Evaluation of Tetracycline Hydrochloride.

Analytical methods based on the mass balance approach were developed for the purity evaluation of tetracycline hydrochloride, a representative salt compound used in pure veterinary drug analysis. The purity assignment method was used to quantify individual classes of impurities via independent analytical techniques. The mass fraction of the free base or salt form contained in a high-purity organic compound with a hydrochloride salt can be determined. The chloride content by ion chromatography-conductivity detector (IC-CD) and general classes of impurities, including structurally related impurities by liquid chromatography-ultraviolet (LC-UV) detector, water by Karl Fischer (KF) coulometric titration, residual solvents by headspace sampler gas chromatography/mass spectrometry (HS-GC/MS), and non-volatiles by thermogravimetric analyzer (TGA), were considered to calculate the purity of the mass fraction. The chloride content of the salt compound can be considered the main impurity in the mass fraction of the free base in the salt compound. A purity assay using quantitative nuclear magnetic resonance (q-NMR) as a direct determination method was performed to confirm the results of the mass balance method. The assigned purities of the tetracycline free form and its salt form in mass fraction were (898.80 ± 1.60) mg/g and (972.65 ± 1.58) mg/g, respectively, which are traceable to the international system of units (SI). Thus, the procedure for evaluating the purity of the free base and salt forms in the salt compound is newly demonstrated in this study.